The main idea behind this project was:
"How small can I make a PDF generator for it to still be useful for 80% of common PDF generation needs?"
The result is a single .go file with less than 1999 lines of code, about 400 of which are color and glyph-size constants, and ~350 are comments.
- All the basics for generating PDF documents, enough for generating mundane business reports.
- It's easier to learn about the internals of the PDF format with a small, concise library.
- The current version of the file is indicated in the header (the timestamp).
go get github.com/balacode/one-file-pdfAll types in are prefixed with PDF for public, and 'pdf' for private types. The only type you need to use is PDF, while PDFColorNames are left public for reference.
- Use all built-in PDF fonts: Courier, Helvetica, Symbol, Times, ZapfDingbats, and their variants
- Recognises 144 web colo(u)r names, or any RGB value
- Stream compression can be turned on or off (PDF files normally compress streams to reduce file size, but turning it off helps in debugging or learning about PDF commands)
- Metadata properties: author, creator, keywords, subject and title
- Set the measurement units you want: mm, cm, inches, twips or points
- Draw lines with different thickness
- Filled or outline rectangles, circles and ellipses
- Grayscale PNG images
- Set columns for text (like tab stops on the page)
- Built-in grid option to help measurement and positioning
- Unicode (requires font embedding)
- Font embedding
- PDF encryption
- Paths, curves and complex graphics
package main
import "fmt"
import "github.com/balacode/one-file-pdf"
func main() {
fmt.Println(`Generating a "Hello World" PDF...`)
// create a new PDF using 'A4' page size
var pdf = pdf.NewPDF("A4")
// add a page: this must be done before drawing
pdf.AddPage()
// set the measurement units to centimeters
pdf.SetUnits("cm")
// draw a grid to help us align stuff (just a guide, not necessary)
pdf.DrawUnitGrid()
// draw the word 'HELLO' in orange, using 100pt bold Helvetica font
// - text is placed on top of, not below the Y-coordinate
// - you can use method chaining
pdf.SetFont("Helvetica-Bold", 100).
SetXY(5, 5).
SetColor("Orange").
DrawText("HELLO")
// draw the word 'WORLD' in blue-violet, using 100pt Helvetica font
// note that here we use the colo(u)r hex code instead
// of its name, using the CSS/HTML format: #RRGGBB
pdf.SetXY(5, 9).
SetColor("#8A2BE2").
SetFont("Helvetica", 100).
DrawText("WORLD!")
// draw a flower icon using 300pt Zapf-Dingbats font
pdf.SetX(7).SetY(17).
SetColorRGB(255, 0, 0).
SetFont("ZapfDingbats", 300).
DrawText("a")
// save the file:
// if the file exists, it will be overwritten
// if the file is in use, prints an error message
pdf.SaveFile("hello.pdf")
} //
5ED4
main2018-MAR-08
- New methods DrawCircle(), DrawEllipse(), FillCircle(), FillEllipse()
- New demo demonstrating circles and text wrapping: corporate.pdf ("Synergy Ipsum")
- SetColor(): now allows HTML color values like
"#4C9141 MayGreen", ignores the extra chars. - Log an error when the name of a selected font is unknown.
- Log the specified measurement unit's name when its name is not valid.
2018-MAR-09
- Replaced PDFColor type with standard lib's color.RGBA (import "image/color")
- SetColorRGB(): changed parameters from int to uint8
- Changed PDFPageSize and PDFStandardPageSizes to private structures
- SaveFile() now returns
errorinstead of*PDF, to allow caller to check for IO errors - SetColumnWidths() is no longer limited to 100 columns
- Font names and color names can be specified with spaces, underscores or '-' delimiting words
- Removed module-global PDFErrorHandler, created SetErrorLogger() to set the handler for each PDF instance